Rashid Jamshaid, Saleem Sahar, Awan Saif Ullah, Iqbal A, Kumar Rajeev, Barakat M A, Arshad Muhammad, Zaheer Muhammad, Rafique Mohsin, Awad M
Catalysis for Environment and Energy Laboratory, Department of Environmental Science, Faculty of Biological Sciences, Quaid-i-Azam University Islamabad 45320 Pakistan
Department of Electrical Engineering, NUST College of Electrical and Mechanical Engineering, National University of Science and Technology (NUST) Islamabad Pakistan.
RSC Adv. 2018 Mar 27;8(22):11935-11945. doi: 10.1039/c8ra02077a. eCollection 2018 Mar 26.
A novel visible light active TiO/FeS semiconductor photocatalyst was synthesized by a simple wet chemical process. X-ray diffraction (XRD) was used to analyze the anatase TiO and pyrite structures in FeS/TiO nanocrystals. Scanning electron microscopy (SEM) confirmed the spherical morphology of composite nanocrystals. X-ray photoelectron spectroscopy (XPS) identified the Fe, S, Ti, and O oxidation states of relevant species. Energy dispersive X-ray (EDX) analysis was performed for compositional analysis. The measured band gap of the TiO/FeS nanocomposite system was 2.67 eV, which is smaller than un-doped TiO (3.10 eV) and larger than FeS (1.94 eV). The photocatalytic activity of TiO/FeS was significantly higher than pure FeS for degrading methylene blue (MB) under solar light irradiation due to the increase in visible light absorption, reduction in band gap energy, and better election-hole pair separation. The photocatalytic degradation of MB was investigated under the influence of solution pH, dye concentrations, and varied catalyst dosage. The optimum degradation (100%) of MB was observed in 180 min and the photocatalysis of MB reduced as the dye concentrations in the solution increased from 15 to 75 mg L. These results prove that the TiO/FeS nanocomposite has the stability, recycling, and adaptability for its practical application as a visible light photocatalyst for wastewater treatment. TiO/FeS showed increased degradation of the organic pollutant; which is confirmed by the increased rate of chemical reaction following pseudo first-order reaction kinetics with the highest rate constant value of 0.0408 m having highest value of 0.9981.
通过简单的湿化学工艺合成了一种新型可见光活性TiO/FeS半导体光催化剂。利用X射线衍射（XRD）分析了FeS/TiO纳米晶体中的锐钛矿TiO和黄铁矿结构。扫描电子显微镜（SEM）证实了复合纳米晶体的球形形态。X射线光电子能谱（XPS）确定了相关物种的Fe、S、Ti和O氧化态。进行了能量色散X射线（EDX）分析以进行成分分析。TiO/FeS纳米复合体系的测量带隙为2.67 eV，小于未掺杂的TiO（3.10 eV）且大于FeS（1.94 eV）。由于可见光吸收增加、带隙能量降低以及更好的电子-空穴对分离，TiO/FeS在太阳光照射下对亚甲基蓝（MB）的光催化活性明显高于纯FeS。在溶液pH值、染料浓度和不同催化剂用量的影响下研究了MB的光催化降解。在180分钟内观察到MB的最佳降解率（100%），并且随着溶液中染料浓度从15 mg/L增加到75 mg/L，MB的光催化作用降低。这些结果证明，TiO/FeS纳米复合材料作为用于废水处理的可见光光催化剂具有实际应用所需的稳定性、可回收性和适应性。TiO/FeS对有机污染物的降解有所增加；这通过遵循伪一级反应动力学的化学反应速率增加得到证实，最高反应速率常数为0.0408 m，最高 值为0.9981。
